Separation preventing device of fluid pipe, and pipe joint

ABSTRACT

A separation preventing device that prevents separation of a fluid pipe in a pipe axis direction, includes a main body externally fitted to an outer peripheral surface of the fluid pipe and has a recess portion facing the outer peripheral surface; a locking member housed in the recess portion in a tiltable manner and is able to bite into the outer peripheral surface of the fluid pipe; and pressing units that are provided in the main body and press the locking member, wherein the locking member has a plurality of wedge portions in a front-back direction of a pipe axis of the fluid pipe, and is equipped with a projection portion that regulates biting of a front wedge portion of the plurality of wedge portions into the fluid pipe, when the fluid pipe moves to a separation side in the pipe axis direction.

BACKGROUND OF THE INVENTION

Field of the Invention

The present invention relates to a separation preventing device thatprevents separation of a fluid pipe in a pipe axis direction. Moreparticularly, the present invention relates to a separation preventingdevice that has elasticity by which even when unexpected external forcesuch as earthquake occurs in a fluid pipe network formed by connecting aplurality of fluid pipes, a connection portion of the fluid pipe expandsand contracts in the pipe axis direction in response to the externalforce by a predetermined acceptable length, and has earthquakeresistance by which the fluid pipe is prevented from being separatedbeyond the acceptable length.

Description of the Related Art

In a separation preventing device and a pipe joint of the related art,an engaging piece (a locking member) having a plurality of locking claws(wedge portions) is housed in a recess portion of a clamping plate (amain body member) externally fitted onto an outer peripheral surface ofan original pipe (a pipe spigot), the clamping plate (the main bodymember) is provided with a pressing screw (a pressing member), and whenthe external force due to earthquake or the like is generated in adirection of separating the fluid pipe in the pipe axis direction, bypressing the locking claws (the wedge portions) against the outerperipheral surface of the fluid pipe, the locking claws (the wedgeportions) are caused to bite into the fluid pipe to prevent theseparation of the fluid pipe in the pipe axis direction (for example,see Utility Model Publication No. 52-166815 (page 3, FIG. 3)).

Moreover, in the separation preventing device and the pipe joint of therelated art, in a recess portion of a pressing ring (a main body member)externally fitted to an outer peripheral surface of a pipe spigot, apressing bolt (a pressing member) is provided in the pressing ring (themain body member) in which a retaining member (a locking member) havinga plurality of projections (wedge portions) is housed, and when externalforce due to an earthquake or the like is generated in a direction ofseparating the pipe spigot in a pipe axis direction, by pressing theplurality of projections (the wedge portions) against the outercircumferential surface of the pipe spigot, the plurality of projections(the wedge portions) is caused to bite into the pipe spigot, therebypreventing the separation of the pipe spigot in the pipe axis direction(for example, see Japanese Patent Laid-Open No. 2005-3207 (pages 5 to 7,FIGS. 1 to 4)).

Moreover, in the separation preventing device and the pipe joint of therelated art, a wedge member (a locking member) having a plurality ofwedge portions is housed in a recess portion of a pressing ring (a mainbody member) externally fitted to an outer peripheral surface of a pipespigot (a fluid pipe), the main body member is provided with a clampingtool (a pressing member), and when external force due to earthquake orthe like is generated in a direction of separating the fluid pipe in apipe axis direction, by pressing the locking member against the outerperipheral surface of the fluid pipe via an intermediary member (aninterposition member) having a tapered surface, the wedge portion iscaused to bite into the fluid pipe, thereby preventing the separation ofthe fluid pipe in the pipe axis direction (for example, see UtilityModel Publication No. 58-31027 (page 3, FIG. 3)).

Furthermore, in the separation preventing device and the pipe joint ofthe related art, a retainer (a locking member) having a plurality ofwedge portions is housed in a recess portion of a gland (a main bodymember) externally fitted onto an outer peripheral surface of a pipespigot (a fluid pipe) via a holder (an elastic body), and a pressingbolt (a pressing member) is provided in the main body member. Thus, whenthe external force due to an earthquake or the like is generated in adirection of separating the fluid pipe in the pipe axis direction, bypressing the locking member against the outer peripheral surface of thefluid pipe via a contact member (an interposition member), the wedgeportions are caused to bite into the fluid pipe to prevent theseparation of the fluid pipe in the pipe axis direction (for example,see Japanese Utility Model Publication No. 4-1434 (Page 3, FIG. 6))

Patent Document 1: Utility Model Publication No. 52-166815 (page 3, FIG.3)

Patent Document 2: Japanese Patent Laid-Open No. 2005-3207 (pages 5 to7, FIGS. 1 to 4)

Patent Document 3: Utility Model Publication No. 58-31027 (page 3, FIG.3)

Patent Document 4: Utility Model Publication No. 4-1434 (Page 3, FIG. 6)

However, in Utility Model Publication No. 52-166815 (page 3, FIG. 3),when the external force due to earthquake or the like acts in adirection of separating the original pipe, the locking piece tilts, afront locking claw (an original pipe end portion side) is pressed firmlycompared to a rear locking claw (an original pipe opposite end portionside), the pressing force is concentrated on the front locking claw,there is a risk of the front locking claw too deeply biting into theoriginal pipe, and there is a problem in that the outer peripheralsurface of the original pipe and an inner surface lining may be damaged,thereby shortening the life of the original pipe.

Moreover, in Japanese Patent Laid-Open No. 2005-3207 (pages 5 to 7,FIGS. 1 to 4), since a central portion of the retaining member isrestricted between the pressing ring and the pressing bolt, the pressingforce from the pressing bolt is concentrated on the projection of thecentral portion of the retaining member. Meanwhile, since a peripheralside portion extending to a side portion of the retaining member is notheld by the pressing bolt and the peripheral side portion of theretaining member becomes a state of a cantilever, the peripheral sideportion is deformed, and there was a fear of insufficient pressing ofthe projection of the peripheral side portion against the fluid pipe. Asa result, there was a problem in that force is concentrated on theprojection of the central portion of the retaining member, theprojection excessively bites into the pipe spigot, thereby locallydamaging the lining of the pipe spigot, and meanwhile, the peripheralside portion of the retaining member is deformed, and the projection ofthe peripheral side cannot sufficiently bite into pipe spigot.

Moreover, in Utility Model Publication No. 58-31027 (page 3, FIG. 3),when the external force caused by the earthquake or the like isrepeatedly generated in a direction of separating the fluid pipe, and onthe contrary, in a direction of inserting the fluid pipe, since theintermediary member (the interposition member) disposed in the recessportion without a gap in the pipe axis direction is locally concentratedon a contact surface between the pressing member and the locking memberby the repeated external force in the pipe axis direction, and collideswith the contact surface several times, there is a fear of damage tocollision locations of these members, and consequentially there is aproblem in that the separation preventing function of the fluid pipe issignificantly impaired.

Furthermore, in Japanese Utility Model Publication No. 4-1434 (Page 3,FIG. 6), since the retainer (the locking member) is housed in the recessportion in a state of being biased in a circumferential direction of thefluid pipe only at one point by the holder (the elastic body), theretainer (the locking member) in the recess portion of the initialassembling stage is liable to become unstable, and at the time ofassembling the separation preventing device with respect to the pipespigot (the fluid pipe), there is a problem in that the locking memberand the interposition member may fall out of the recess portion.

Furthermore, in order to prevent the locking member and theinterposition member from falling out of the recess portion, whenincreasing the elastic force by changing a material or a shape of theelastic body, since the elastic body still applies high elastic force tothe locking member after assembling, when the external force due to anearthquake or the like is generated in a direction of separating thefluid pipe, there is a problem in that the locking member does not tiltat a predetermined angle and it is not possible to exhibit the lockingforce as designed.

The present invention has been made in view of such problems, and anobject thereof is to provide a separation preventing device of a fluidpipe that is able to prevent the excessive biting of the wedge portionof the locking member into the fluid pipe and is able to prevent thefluid pipe, the locking member, the pressing member, and theinterposition member from being locally concentrated and colliding withone another to prevent damage to these members even when the externalforce due to earthquake or the like and the repeated external forcegenerated in the pipe axis direction act in a direction of separatingthe fluid pipe, and is able to firmly maintain the separation preventingfunction of the fluid pipe.

The present invention has been made in view of such problems, and anobject thereof is to provide a separation preventing device of a fluidpipe in which the locking member can be stably housed without fallingout of the recess portion, and the locking member after assembling canexhibit the locking force as designed.

SUMMARY OF THE INVENTION

In order to solve the above-described problems, according to the presentinvention, there is provided a separation preventing device of a fluidpipe and pipe joint that prevents separation of a fluid pipe in a pipeaxis direction, the separation preventing device including: a main bodymember that is externally fitted to an outer peripheral surface of thefluid pipe and has a recess portion facing the outer peripheral surface;a locking member that is housed in the recess portion in a tiltablemanner and is able to bite into the outer peripheral surface of thefluid pipe; and a pressing unit that is provided in the main body memberand presses the locking member, wherein the locking member has aplurality of wedge portions in a front-back direction of a pipe axis ofthe fluid pipe, and is equipped with a projection portion that regulatesbiting of a front wedge portion of the plurality of wedge portions intothe fluid pipe, when the fluid pipe moves to a separation side in thepipe axis direction.

According to this feature, when the fluid pipe moves in the direction ofbeing separated, among the plurality of wedge portions provided in thefront-back direction of the fluid pipe axis direction, a wedge portionprovided on a front side bites into the fluid pipe, but biting of thefront wedge portion is regulated by the projection portion provided inthe locking member. Accordingly, the excessive biting of the front wedgeportion into the fluid pipe is suppressed, thereby being able to preventthe damage to the fluid pipe.

In the separation preventing device of the fluid pipe and pipe joint ofthe present invention, the projection portion may be provided betweenthe front wedge portion and the rear wedge portion of the plurality ofwedge portions.

According to this feature, since the projection portion is providedbetween the front wedge portion and the rear wedge portion, after thefront wedge portion somewhat bites into the fluid pipe, the projectionportion regulates biting of the front wedge portion into the fluid pipe,and thus, it is possible to prevent the front wedge portion fromexcessively biting into the fluid pipe.

In the separation preventing device of the fluid pipe and pipe joint ofthe present invention, the projection portion may be a wedge portionthat bites into the fluid pipe at least by tilting.

According to this feature, in addition to the front wedge portion thatbites into the fluid pipe at least by tilting, since the projectionportion also bites into the fluid pipe at least by tilting, the frontwedge portion and the projection portion are able to firmly prevent theseparation of the fluid pipe in the pipe axis direction in combination.

In the separation preventing device of the fluid pipe and pipe joint ofthe present invention, a leading end of the projection portion does notproject from a line that connects a leading end of the front wedgeportion and a leading end of the rear wedge portion.

According to this feature, since the leading end of the projectionportion does not project from the line that connects the leading end ofthe front wedge portion and the leading end of the rear wedge portion,after the front wedge portion bites into the fluid pipe by tilting, theprojection portion bites into the fluid pipe. Accordingly, it is alsopossible to prevent the front wedge portion from excessively biting intothe fluid pipe and to adjust the amount of biting of the front wedgeportion by adjusting the amount of projection of the leading end of theprojection portion.

In the separation preventing device of the fluid pipe and pipe joint ofthe present invention, the wedge portion may tilt to a front side in thepipe axis direction of the fluid pipe.

According to this feature, since the wedge portion tilts to the frontside in the pipe axis direction of the fluid pipe, it is possible toreliably prevent the movement of the fluid pipe to the separation sidein the pipe axis direction.

In the separation preventing device of the fluid pipe and pipe joint ofthe present invention, the locking member may have a central portion, aperipheral side portion extending to a lateral side of the centralportion, and is equipped with a contact portion with which theperipheral side portion and the recess portion come into contact in astate in which the central portion of the locking member and the recessportion are spaced apart from each other.

According to this aspect, when the fluid pipe moves in the separationdirection, the peripheral side portion of the locking member issupported by the contact portion, in a state in which the deformation ofthe peripheral side portion of the locking member is suppressed, thewedge portion of the peripheral side portion can reliably bite into thepipe spigot. Meanwhile, in the state in which the central portion of thelocking member and the recess portion are spaced from each other, thewedge portion of the central portion is able to moderately bite into thepipe spigot, and it is possible to prevent damage to the lining of thefluid pipe.

In the separation preventing device of the fluid pipe and pipe joint ofthe present invention, the peripheral side portion of the locking membermay be equipped with a peripheral side portion inclined surface thattilts toward an inner side in a radial direction of the fluid pipe andtoward a front side in the pipe axis direction of the fluid pipe fromthe contact portion.

According to this aspect, since the peripheral side portion of thelocking member is equipped with the peripheral side portion inclinedsurface that tilts toward an inner side in a radial direction of thefluid pipe and toward a front side in the pipe axis direction of thefluid pipe from the contact portion, even after the peripheral sideportion comes into contact with the recess portion, the locking membercan further tilt and can further bite into the pipe spigot. Accordinglyit is possible to firmly prevent the separation of the fluid pipe in thepipe axis direction.

In the separation preventing device of the fluid pipe and pipe joint ofthe present invention, a dimension in the pipe axis direction of thecentral portion of the locking member may be formed to be greater than adimension in the pipe axis direction of the peripheral side portion ofthe locking member.

According to this feature, since the dimension in the pipe axialdirection of the central portion of the locking member is formed to begreater than the dimension in the pipe axis direction of the peripheralside portion, it is possible to reliably hold the bending moment appliedto the peripheral side portion of the locking member.

In the separation preventing device of the fluid pipe and pipe joint ofthe present invention, the recess portion may be equipped with apressing wall coming into contact with the peripheral side portion ofthe locking member, and a rear side wall facing the central portion ofthe locking member.

According to this feature, since the recess portion is equipped with thepressing wall coming into contact with the peripheral side portion ofthe locking member, and the rear side wall facing the central portion ofthe locking member, when the fluid pipe moves in the separationdirection, the peripheral side of the locking member is supported whilecoming into contact with the pressing wall of the recess portion, andthus, it is possible to reduce the deformation of the peripheral sideportion. Since the central portion of the locking member faces the rearside wall of the recess portion, the wedge portions of the centralportion press the pipe spigot, while allowing the moderate movement andtilting. Accordingly, it is possible to prevent the excessive bitinginto the pipe spigot and to prevent damage to the lining of the pipespigot.

In the separation preventing device of the fluid pipe and pipe joint ofthe present invention, the separation preventing device including aninterposition member interposed between the locking member and thepressing member, wherein the interposition member is equipped with atapered surface coming into contact with an outer surface of the lockingmember, and is housed in the recess portion in a state of having anacceptable movement value of a predetermined width in the pipe axisdirection of the fluid pipe.

According to this feature, even when the external force of separating orinserting in the pipe axis direction is applied to the fluid pipe, asthe interposition member between the locking member and the pressingmember moves in the recess portion of the main body member in the pipeaxis direction by an acceptable value of a predetermined width, thetapered surface of the interposition member changes a contact portionwith the outer surface of the locking member. Accordingly, even when theexternal force in the pipe axis direction of separating and insertingthe fluid pipe is repeated, since it is possible to disperse the mutualcontact locations of the locking member, the pressing member, and theinterposition member, without being locally concentrated to one anotherwhile colliding with one another, it is possible to prevent damage tothese members due to the repeated concentration collision and to firmlyhold the separation preventing function of the fluid pipe, thereby beingable to satisfactorily hold a piping structure of the initialconnection.

In the separation preventing device of the fluid pipe and pipe joint ofthe present invention, the outer surface of the locking member may beformed on the inclined surface that comes into contact with the taperedsurface of the interposition member substantially in parallel.

According to this feature, since both the tapered surface of theinterposition member and the inclined surface of the locking member comeinto contact with each other substantially in parallel in a tiltingstate, it is possible to ward off the external force by thesliding-contact between the parallel surfaces tilting with respect tothe pipe axis direction, without directly receiving the external forceacting in the pipe axis direction.

In the separation preventing device of the fluid pipe and pipe joint ofthe present invention, the interposition member may be equipped with apressing target surface that comes into contact with the pressingsurface of the pressing member in a tiltable manner.

According to this feature, as the interposition member moves in therecess portion of the main body member by an acceptable value of apredetermined width in the pipe axis direction, by tilting theinterposition member with respect to the pressing member, it is possibleto hold the pressing force so that the locking member, the interpositionmember, and the pressing member are not separated from one another, evenby the movement of the interposition member.

In the separation preventing device of the fluid pipe and pipe joint ofthe present invention, the pressing member may be provided in the mainbody member so as to be movable back and forth in a radial direction ofthe fluid pipe.

According to this feature, since the pressing member is provided on themain body member so as to be movable back and forth in the radialdirection of the fluid pipe, during operation of moving the pressingmember back and forth in the radial direction, an operating means suchas a tool is not interfered by the outer surface of the fluid pipe.

In the separation preventing device of the fluid pipe and pipe joint ofthe present invention, a rear edge of the pressing surface of thepressing member, a rear end surface of the interposition member, and arear end surface of the locking member may be sequentially disposed fromthe rear in the pipe axis direction of the fluid pipe.

According to this feature, since the interposition member does notcontact with the rear edge of the pressing surface of the pressingmember, it is possible to prevent damage to the rear edge, and it ispossible to vary a tilting center of the interposition member and atilting center of the locking member in the pipe axis direction.Accordingly, it is possible to increase the variation of the tiltingaspect of the interposition member and the locking member and alwayspress the locking member in response to various directions andmagnitudes of the external force.

In the separation preventing device of the fluid pipe and pipe joint ofthe present invention, wherein at an end portion of the locking memberin a circumferential direction of the fluid pipe, a fitting grooveconfigured to fit an anti-falling elastic body of the locking memberfrom the recess portion is formed tapering toward an outer diameterdirection of the fluid pipe.

According to this aspect, since the elastic restoring force of theelastic body fitted to the fitting groove formed tapering toward theouter diameter direction of the fluid pipe acts stronger as it goestoward the outer diameter side, the locking member can be reliablyhoused without falling out of the recess portion, and furthermore whenthe locking member housed in the recess portion moves or tilts, sincethe elastic body fitted into the fitting groove follows the movement ofthe locking member, the elastic body is not detached from the recessportion and does not affect the movement and tilting of the lockingmember, and thus, the locking member can move or tilt as designed.

In the separation preventing device of the fluid pipe of the presentinvention, the fitting grooves may be formed between a plurality ofwedge portions provided on the locking member.

According to this feature, since it is possible to form the fittinggroove by effectively utilizing a space between the plurality of wedgeportions without dominating the regions of the several wedge portions,the locking capability of the locking member is not affected.

In the separation preventing device of the fluid pipe of the presentinvention, the fitting grooves of the locking member may be formed topenetrate in a radial direction of the fluid pipe.

According to this aspect, since the elastic body elastically deformed inthe penetration direction of the fitting groove comes into contact withthe recess portion inner wall or the outer surface of the fluid pipe,the elastic body can be made to function as a cushioning material.

A pipe joint of the present invention includes the fluid pipe, a pipeSocket into which a front end portion of the fluid pipe is inserted, anda separation preventing device of a fluid pipe that prevents separationof the fluid pipe from the pipe socket.

According to this feature, since it is possible to firmly prevent theseparation of the fluid pipe from the pipe socket using the separationpreventing device of the fluid pipe, it is possible to provide a pipejoint having excellent earthquake resistance and elasticity.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a side cross-sectional view of a pipe joint equipped with aseparation preventing device in an exemplary embodiment.

FIG. 2(a) is a partial cross-sectional view of the separation preventingdevice as viewed from an arrow A of FIG. 1, and FIG. 2(b) is a view asviewed from an arrow B in FIG. 2(a).

FIG. 3(a) is a front view of a state in which a locking member and aninterposition member are combined with each other, and FIG. 3(b) is apartial side cross-sectional view of FIG. 3(a).

FIG. 4 is a side cross-sectional view of the separation preventingdevice.

FIG. 5(a) is a side cross-sectional view of the separation preventingdevice before the initial clamping of the pressing member, and FIG. 5(b)is a side cross-sectional view of the separation preventing device afterthe initial clamping of the pressing member.

FIG. 6(a) is a side cross-sectional view illustrating the behavior ofthe separation preventing device when a pipe spigot starts to move tothe separation side in the pipe axis direction of the fluid pipe, andFIG. 6(b) is a side cross-sectional view illustrating the behavior ofthe separation preventing device when the pipe spigot further moves tothe separation side in the pipe axis direction of the fluid pipe.

FIG. 7 is a side cross-sectional view illustrating a final state of thebehavior of the separation preventing device when the pipe spigot movesto the separation side in the pipe axis direction of the fluid pipe.

FIG. 8(a) is a side cross-sectional view illustrating a modified exampleof the locking member, and FIG. 8(b) is a side cross-sectional viewillustrating another modified example of the locking member.

FIG. 9(a) is a side cross-sectional view of the separation preventingdevice before an initial clamping of the pressing member taken from across-section X-X of FIG. 2 and FIG. 9(b) is a side cross-sectional viewtaken from a cross-section Y-Y.

FIG. 10(a) is a side cross-sectional view of the separation preventingdevice after the initial clamping of the pressing member taken from thecross-section X-X of FIG. 2 and FIG. 10(b) is a side cross-sectionalview taken from the cross-section Y-Y.

FIG. 11(a) is a side cross-sectional view of the separation preventingdevice when the pipe spigot starts to move to the separation side in thepipe axis direction taken from the cross-section X-X of FIG. 2, and FIG.11(b) is a side cross-sectional view taken from the cross-section Y-Y.

FIG. 12(a) is a side cross-sectional view of the separation preventingdevice when the pipe spigot further moves to the separation side in thepipe axis direction of the fluid pipe taken from the cross-section X-Xof FIG. 2, and FIG. 12(b) is a side cross-sectional view taken from thecross-section Y-Y.

FIG. 13(a) is a side cross-sectional view illustrating a final state ofthe separation preventing device when the pipe spigot moves to theseparation side in the pipe axis direction of the fluid pipe taken fromthe cross-section X-X of FIG. 2, and FIG. 13(b) is a sidecross-sectional view taken from the cross-section Y-Y.

FIG. 14(a) is a side cross-sectional view illustrating the behavior ofthe separation preventing device when the pipe spigot starts to movefrom an initial clamping state to a separation side in the pipe axisdirection, and FIG. 14(b) is a side cross-sectional view illustratingthe behavior of the separation preventing device when the pipe spigotfurther moves to the separation side in the pipe axis direction of thefluid pipe.

FIG. 15(a) is a side cross-sectional view illustrating the behavior ofthe separation preventing device when the pipe spigot moves to theinsertion side in the pipe axis direction of the fluid pipe, and FIG.15(b) is a side cross-sectional view illustrating the behavior of theseparation preventing device when the pipe spigot moves to theseparation side in the pipe axis direction of the fluid pipe again.

FIG. 16 is a side cross-sectional view illustrating a first modifiedexample of the interposition member.

FIG. 17 is a side cross-sectional view illustrating a second modifiedexample of the interposition member.

FIG. 18 is a side cross-sectional view illustrating a situation in whicha bolt of the separation preventing device is clamped.

FIG. 19 is a side view illustrating a state in which the elastic body isfitted into the fitting groove of the locking member.

FIG. 20 is a view illustrating a state in which the elastic restoringforce of the elastic body acts on the locking member and theinterposition member.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Hereinafter, embodiments for carrying out a separation preventing deviceaccording to the present invention will be described based on theexamples.

Example 1

A separation preventing device according to the example 1 will bedescribed with reference to FIGS. 1 to 8. Hereinafter, the descriptionwill be provided by assuming that an insertion side of a pipe spigot 2of FIG. 1 to a pipe socket 3 is a front side (front) in a pipe axisdirection, and a separation side of the pipe spigot 2 from the pipesocket 3 is a rear side (rear) in the pipe axis direction.

As illustrated in FIG. 1, a pipe joint 1 of the present example isequipped with the pipe socket 3 having a receiving unit 3 a formed at anend portion thereof, a pipe spigot 2 as a fluid pipe of the presentinvention inserted into the receiving unit 3 a, a separation preventingdevice 10 provided on an outer peripheral surface 2 b of the pipe spigot2, and sealing member 5 disposed between an inner circumferentialsurface of the receiving unit 3 a and the outer peripheral surface 2 bof the insertion unit 2 a along a circumferential direction.Furthermore, the sealing member 5 is pressed in the pipe axis directionby an annular convex portion 11 d formed in a main body member 11 to bedescribed later, the sealing member 5 comes into close contact with theinner circumferential surface of the receiving unit 3 a and the outerperipheral surface 2 b of the insertion unit 2 a, and thus, the pipesocket 3 and the pipe spigot 2 are connected to each other in a sealingmanner.

Furthermore, the pipe joint 1 of the present invention is a part of apipe constituting a pipe network, and the pipe socket 3 and the pipespigot 2 buried in the ground are, for example, made of ductile castiron for water supply, and the inner peripheral surface of the pipe iscoated with a mortar layer. Furthermore, the fluid pipe according to thepresent invention may be made of metal, such as another cast iron andsteel, asbestos, concrete, polyvinyl chloride, polyethylene, polyolefinor the like. Furthermore, the inner peripheral surface of the fluid pipemay be coated with, for example, epoxy resin or the like, without beinglimited to a mortar layer, or a suitable material may be coated on theinner peripheral surface of the fluid pipe by powder coating. Moreover,in the present invention, the fluid in the fluid pipe is not limited tothe clean water of the present embodiment, and may be, for example, gas,a gas-liquid mixture of gas and liquid, other than industrial water,agricultural water, sewage or the like.

Furthermore, as illustrated in FIG. 1, the separation preventing device10 according to the present invention disposed on the outer peripheralsurface 2 b of the pipe spigot 2 is mainly constituted by a main bodymember 11 that is externally fitted to the outer peripheral surface 2 bof the pipe spigot 2 and has a recess portion 12 facing the outerperipheral surface 2 b, a locking member 15 that is housed in the recessportion 12 in a tiltable manner and can bite into the outer peripheralsurface 2 b of the pipe spigot 2, and a pressing unit that is providedin the main body member 11 and includes a bolt 13 and an interpositionmember 14 as a pressing member configured to press the locking member15.

The separation preventing device 10 is configured so that the main bodymember 11 is connected and fixed with respect to the receiving unit 3 aby a fastening member 4, and the locking member 15 housed in the recessportion 12 of the main body member 11 is locked on the outer peripheralsurface 2 b of the pipe spigot 2 as will be described later, which makesit possible to prevent the insertion unit 2 a from being separated fromthe receiving unit 3 a. Hereinafter, the members constituting theseparation preventing device 10 will be described.

First, the main body member 11 will be described. As illustrated FIGS.1, 2, and 4, the main body member 11 is a gland of an annular integralmember capable of being externally fitted onto the outer peripheralsurface 2 b of the pipe spigot 2, and is formed by ductile cast iron,stainless steel, steel, cast steel or the like. Furthermore, the mainbody member of the present invention may have a structure that can bedivided into a predetermined number in the circumferential direction. Aplurality of the recess portions 12 are circumferentially formed on theinner peripheral portion of the main body member 11 that faces the outerperipheral surface 2 b of the pipe spigot 2. The interior of each of therecess portions 12 is a space surrounded by a front side wall 12 a and apressing wall 12 b formed in the pipe axis direction of the pipe spigot2 at a predetermined gap, peripheral walls 12 d and 12 d formed in thecircumferential direction of the pipe spigot 2, and a bottom wall 12 c,and the recess portion 12 has a bottom housing unit 12 e that houses theinterposition member 14. The locking member 15 and the interpositionmember 14 to be described later are housed in the recess portion 12.

As illustrated in FIGS. 2(a) and 4, the main body member 11 isconfigured so that a flange unit 11 a and a housing unit 11 b having therecess portion 12 therein are formed alternately in the circumferentialdirection, the flange unit 11 a is clamped by the flange unit 3 b of thepipe socket 3 and the fastening member 4, and the main body member 11and the pipe socket 3 are integrally fixed. The above-described recessportion 12 is formed on the inner peripheral portion of the housing unit11 b, and a female screw unit 11 c is formed on the outer peripheralportion of the housing unit lib in the radial direction. The bolt 13 asthe pressing member of the present invention is screwed into the femalescrew unit lie, and by clamping the bolt 13, it is possible to press thelocking member 15 against the outer peripheral surface 2 b of the pipespigot 2 via the interposition member 14.

Furthermore, as illustrated in. FIGS. 1 and 4, on the end surface of themain body member 11 facing the receiving unit 3 a, an annular convexportion 11 d configured to press the sealing member 5 is formed. Byclamping the fastening member 4, the sealing member 5 is pressed in thepipe axis direction by the annular convex portion 11 d, and thereceiving unit 3 a and the insertion unit 2 a are connected to eachother in a sealing manner.

Next, the locking member 15 will be described. As illustrated in FIGS.3(b) and 4, the locking member 15 has an asymmetrical polygonal shape asviewed in peripheral side view and cross-sectional side view, asillustrated in FIG. 3(a), the locking member 15 is a substantiallyarcuate member having a predetermined width in the circumferentialdirection that is equipped with a front wedge portion 17, a rear wedgeportion 16, and an auxiliary wedge portion 18 as a projection portion onthe inner peripheral portion thereof arcuately. The locking member 15 ismade of ductile cast iron, steel, stainless steel or the like.Furthermore, the locking member 15 is formed with a convex portion 15 bhaving an inclined surface 15 a on the outer peripheral portion of thecenter in the circumferential direction, and the inclined surface 15 aincreases in diameter and tilts so as to be away from the outerperipheral surface 2 b of the pipe spigot 2 as it goes toward the frontin the pipe axis direction of the pipe spigot 2.

On the side facing the outer peripheral surface 2 b of the pipe spigot 2of the locking member 15, the plurality of wedge portions 16, 17, and 18are formed in the pipe axis direction at a predetermined gap. The frontwedge portion 17 is formed on the front side in the pipe axis directionon which the distance from the outer peripheral surface of the pipespigot 2 to the inclined surface 15 a of the locking member 15 in thepipe radial direction is relatively large, the rear wedge portion 16 isformed on the rear side in the pipe axis direction on which the distancefrom the outer peripheral surface of the pipe spigot 2 to the inclinedsurface 15 a in the pipe radial direction is relatively small, and theauxiliary wedge portion 18 as the projection portion of the presentinvention is formed between the front wedge portion 17 and the rearwedge portion 16 in the pipe axis direction.

As illustrated in FIG. 4, the cross-sectional shapes of the respectivewedge portions 16, 17, and 18 are a triangular shape including a surfacethat tilts toward the front side in the pipe axis direction of the pipespigot 2 and a surface extending outward in the pipe radial direction ofthe pipe spigot 2 (the outward radial direction) substantiallyperpendicular to the outer peripheral surface of the pipe spigot 2, andthe respective wedge portions 16, 17, and 18 have a tapered shapetilting to the front side in the pipe axis direction toward the outercircumferential surface of the pipe spigot 2 from the proximal end.

Furthermore, as illustrated in FIGS. 2(a), 3(a) and 3(b), the innerdiameter dimensions (the radial dimensions as viewed in the pipe axisdirection) and the circumferential dimensions of the leading ends of therespective wedge portions 16, 17, and 18 formed in an arc are set to thedimensions biting into the pipe spigot 2 over substantially the entirelength in the circumferential direction of the respective wedge portions16, 17, and 18 when pressing the locking member 15 by the bolt 13 orwhen the locking member 15 tilts as will be described later. Acircumferential length S1 of the front wedge portion 17 and the rearside wedge portion 16 is formed to be substantially equal and is set tobe greater than a circumferential length S2 of the auxiliary wedgeportion 18 as the projection portion. Furthermore, an amount ofprojection in an inner diameter direction of the auxiliary wedge portion18 is set to be smaller than an amount of projection in the innerdiameter direction of the front wedge portion 17 and the rear side wedgeportion 16, and more specifically, as illustrated in FIGS. 3(a) and3(b), the leading end of projection in the inner diameter direction ofthe auxiliary wedge portion 18 formed in an arc is set at a position ofa predetermined dimension δ on the outside in the radial direction (theoutward radial direction) from the line that connects the leading endsof the front wedge portion 17 and the rear wedge portion 16.

Next, the interposition member 14 will be described. The interpositionmember 14 constitutes the pressing unit together with the bolt 13 as thepressing member. As illustrated in FIGS. 3(a), 3(b), and 4, theinterposition member 14 has a groove portion along the pipe axisdirection of the fluid pipe, and the bottom of the groove portion is atapered surface 14 a. The interposition member 14 is provided so thatthe groove portion covers the convex portion 15 b of the locking member15, the tapered surface 14 a of the interposition member 14 and theinclined surface 15 a of the convex portion 15 b are in contact witheach other in a slidable manner, and the locking member 15 is movablealong the tapered surface 14 a of the interposition member 14 ortiltable in contact with the tapered surface 14 a.

The separation preventing device 10 including the above-described mainbody member 11, the locking member 15, the bolt 13, and theinterposition member 14 is assembled as follows. As illustrated in FIGS.1, 2 and 4, the interposition member 14 is housed in the bottom housingunit 12 e of the main body member 11, in a state of holding an elasticbody 19 into a fitting groove 15 d of a circumferential end portion ofthe locking member 15, the locking member 15 is inserted into the recessportion 12 of the main body member 11, and the locking member 15 is heldin the recess portion 12. Furthermore, the main body member 11 in whichthe interposition member 14 and the locking member 15 are housed isexternally fitted to the insertion unit 2 a of the pipe spigot 2 in aloosely fitted state, and the sealing member 5 is externally fitted tothe outer peripheral surface 2 b of the insertion unit 2 a of the frontend side thereof at a predetermined position.

Next, in a state the main body member 11 and the sealing member 5 areexternally fitted to the insertion unit 2 a, which is inserted into thereceiving unit 3 a, and the main body member 11 is fastened to the pipesocket 3 while pressing the sealing member 5 between the insertion unit2 a and the receiving unit 3 a by the fastening member 4 and is set toan initial assembling position, the bolt 13 screwed into the femalescrew unit 11 e of the housing unit 11 b of the main body member 11 isscrewed, and the initial clamping of the bolt 13 is performed bypredetermined clamping torque.

Next, the behavior of the separation preventing device 10 when force isapplied in the separation direction of the pipe axis of the pipe spigot2 from the start of the initial clamping of the bolt 13 screwed into themain body member 11 will be described.

As illustrated in FIG. 5(a), the center of the bolt 13 screwed into themain body member 11 is set at a position shifted rearward from thecenter position of the length dimension in the pipe axis direction ofthe interposition member 14, and at a position shifted to the rear sideof the pipe axis from the position of the rear wedge portion 16 of thelocking member 15. Furthermore, gaps that allow the movement and tiltingof the interposition member and the locking member are formed betweenthe interposition member 14 and the bottom housing unit 12 e, andbetween the locking member 15 and the recess portion 12. For thatreason, when the bolt 13 is initially slightly clamped, theinterposition member 14 moves to the rear side in the pipe axisdirection of the pipe spigot 2 and is set in the state of coming intocontact with the rear side wall 12 f of the bottom housing unit 12 e, orthe locking member 15 is set in the state of coming into contact withthe front side wall 12 a of the recess portion of the main body member11 while tilting in a counterclockwise direction. Moreover, in the statein which the locking member 15 tilts in the counterclockwise direction,the rear wedge portion 16 slightly comes into contact with the outerperipheral surface 2 b of the pipe spigot 2, and the front wedge portion17 and the auxiliary wedge portion 18 become the non-contact state fromthe outer peripheral surface 2 b of the pipe spigot 2 with clearances c1and c2, respectively.

Next, as illustrated in FIG. 5(b), when clamping the bolt 13 bypredetermined initial clamping torque, since the center of the bolt 13is shifted to the rear side of the pipe axis from the position of therear wedge portion 16 of the locking member 15, the initial clampingforce due to the bolt 13 is mainly concentrated on the rear wedgeportion 16 of the locking member 15, and the rear wedge portion 16mainly bites into the outer peripheral surface 2 b of the pipe spigot 2.Furthermore, the front wedge portion 17 becomes a state of non-contactwith the pipe spigot 2 or a state of slight-contact with the pipe spigot2, and the auxiliary wedge portion 18 maintains the non-contact statewith a clearance c3 from the outer peripheral surface 2 b of the pipespigot 2. Furthermore, since the pressing surface 13 a of the bolt 13 isformed in a plane, the bolt 13 is able to press a pressing targetsurface 14 b of the interposition member 14 over a wide range, and isable to allow the wedge portions 16, 17, and 18 to equally bite into theouter peripheral surface 2 b of the pipe spigot 2 substantially over theentire length of the circumferential length thereof. Accordingly it ispossible to prevent the wedge portions 16, 17 and 18 from unevenlybiting into the outer peripheral surface 2 b of the pipe spigot 2.

Next, when the separating force is exerted in the pipe axis direction ofthe pipe spigot 2 from the initial clamping state, as illustrated inFIG. 6(a), an O point of the biting portion of the pipe spigot 2 of therear wedge portion 16 of the locking member 15 moves backward in thepipe axis direction together with the pipe spigot 2, and the lockingmember 15 is pressed from the interposition member 14 by the wedgeeffect. Then, the locking member 15 tilts about the O point of the rearwedge portion 16 in a clockwise direction, the rear wedge portion 16 andthe front wedge portion 17 bite into the outer peripheral surface 2 b ofthe pipe spigot 2, and the auxiliary wedge portion 18 does not come intocontact with or slightly come into contact with the outer peripheralsurface 2 b of the pipe spigot 2. Furthermore, the separating force inthe pipe axis direction of the pipe spigot 2 in this state is held bythe two wedge portions of the front wedge portion 17 and the rear wedgeportion 16 of the locking member 15.

When the pipe spigot 2 further moves backward in the pipe axisdirection, as illustrated in FIG. 6(b), the amount of biting of thefront wedge portion 17 and the rear wedge portion 16 into the outerperipheral surface 2 b of the pipe spigot 2 further increases. Then, theauxiliary wedge portion 18 as the projection portion starts to bite intothe pipe spigot 2. When the auxiliary wedge portion 18 starts to biteinto the pipe spigot 2, since the pressing force to the locking member15 from the interposition member 14 is also held by the auxiliary wedgeportion 18, biting of the front wedge portion 17 into the outerperipheral surface 2 b is regulated. Furthermore, in this state, theseparating force in the pipe axis direction of the pipe spigot 2 is heldby the three wedge portions of the front wedge portion 17, the rearwedge portion 16, and the auxiliary wedge portion 18 as the projectionportion.

Moreover, the locking member 15 is pressed by the interposition member14, and finally, as illustrated in FIG. 7, the three wedge portions ofthe front wedge portion 17, the rear wedge portion 16, and the auxiliarywedge portion 18 further bite into the pipe spigot 2, and the separatingforce in the pipe axis direction of the pipe spigot 2 matches with thelocking force generated in each of the wedge portions 16, 17, and 18,thereby being able to hold the separating force in the pipe axisdirection of the pipe spigot 2.

Furthermore, the shapes and the dimensions of the wedge portions are setwith a sufficient margin with respect to the separating force assumed indesign.

In particular, even when the separating force assumed in design isapplied to the separation preventing device and the wedge portions biteinto the pipe spigot 2, bottoms 15 e among the wedge portions 16, 17,and 18 are set to be separated without coming into contact with theouter peripheral surface 2 b of the pipe spigot 2. If the setting asstated above is not done, it causes a problem when the separating forceassumed in design is applied to the separation preventing device, thatthe bottoms 15 e among the wedge portions 16, 17, and 18 are in thestate of coming into contact with the outer peripheral surface 2 b ofthe pipe spigot 2, and thus the wedge portions 16, 17, and 18 cannotbite into the pipe spigot 2 anymore and are not able to hold the largerseparating force. Furthermore, it causes a problem that the situationwhere the pipe spigot 2 is subjected to the large pressing force fromboth the wedge portions 16, 17, and 18 and the bottoms 15 e among thewedge portions, and thus the pipe spigot 2 is significantly reduced indiameter, and the linings of the inner peripheral surface and the outerperipheral surface are damaged.However, the present invention can prevent such the problems becauseeven when the separating force assumed in design is applied to theseparation preventing device and the wedge portions bite into the pipespigot 2, bottoms 15 e among the wedge portions 16, 17, and 18 are setto be separated without coming into contact with the outer peripheralsurface 2 b of the pipe spigot 2.

The separation preventing device of the present invention according tothe example 1 exhibits the following effects.

In the state of performing the initial clamping of the bolt 13 screwedto the main body member 11 with respect to the pipe spigot 2, when theseparating force is exerted on the pipe spigot 2 in the pipe axisdirection, the locking member 15 tilts, and the front wedge portion 17bites into the pipe spigot 2. Moreover, when the locking member 15further tilts, the auxiliary wedge portion 18 as the projection portionstarts to bite into the pipe spigot 2, biting of the front wedge portion17 into the pipe spigot 2 is regulated by biting of the auxiliary wedgeportion 18, and thus, it is possible to prevent the front wedge portion17 from excessively biting into the pipe spigot 2. Accordingly, sincethe pipe spigot 2 is not subjected to the excessive pressure from thefront wedge portion 17, the separation preventing device is able toprevent damage to the outer peripheral surface and the linings of theinner surface.

Since the auxiliary wedge portion 18 as the projection portion isprovided between the front wedge portion 17 and the rear wedge portion16, after the front wedge portion 17 somewhat bites into the pipe spigot2, the auxiliary wedge portion 18 starts biting to regulate the bitingof the front wedge portion 17 into the pipe spigot 2, and thus, it ispossible to prevent the front wedge portion from locally biting into thepipe spigot 2.

Since the auxiliary wedge portion 18 is the wedge portion that bitesinto the pipe spigot 2 by tilting of the locking member 15, in additionto the front wedge portion 17 biting into the pipe spigot 2 by tilting,the auxiliary wedge portion 18 also bites into the pipe spigot 2 bytilting. Accordingly, the front wedge portion 17 and the auxiliary wedgeportion 18 are able to firmly prevent the separation of the pipe spigot2 in the pipe axis direction in combination.

Since the leading end of the auxiliary wedge portion 18 does not projectfrom the line that connects the leading end of the front wedge portion17 and the leading end of the rear wedge portion 16, after the frontwedge portion 17 bites into the pipe spigot 2 by tilting, the auxiliarywedge portion 18 bites into the pipe spigot 2. Accordingly, it ispossible to prevent the front wedge portion 17 from excessively bitinginto the pipe spigot 2 and to adjust the amount of biting of the frontwedge portion 17 by adjusting the amount of projection of the leadingend of the auxiliary wedge portion 18.

The cross-sectional shapes of each of the wedge portions 16, 17, and 18are a triangle that includes a surface tilting toward the front side inthe pipe axis direction of the pipe spigot 2 and a surface extendingoutward in the radial direction of the pipe spigot 2 (the outward radialdirection) substantially perpendicular to the outer peripheral surface 2b of the pipe spigot 2, and have a tapered shape toward the outerperipheral surface of the pipe spigot 2 from its proximal end.Accordingly, each of the wedge portions 16, 17, and 18 easily bites intothe outer peripheral surface 2 b of the pipe spigot 2, the surfaceextending outward in the radial direction of the pipe spigot 2 (theoutward radial direction) substantially perpendicular to the outerperipheral surface 2 b of the pipe spigot 2 can firmly hold theseparating force, and thus, it is possible to firmly prevent theseparation of the pipe spigot 2 in the pipe axis direction.

Since the pipe joint 1 is equipped with the pipe spigot 2, the pipesocket 3 to which a front end portion 2 c of the pipe spigot 2 isinserted, and the separation preventing device 10 that prevents theseparation of the pipe spigot 2 from the pipe socket 3, the pipe joint 1is able to reliably prevent the pipe spigot 2 from being separated fromthe pipe socket 3.

The example 1 of the present invention have been described above withreference to the drawings, but the specific structure is not limited tothese examples, and modifications and additions are also included in thepresent invention within the scope that does not depart from the scopeof the present invention.

For example, in the above-described example 1, the tapered surface ofthe interposition member and the inclined surface of the locking memberwere a plane, but is not limited thereto, in order to reduce the contactarea between the tapered surface of the interposition member and theinclined surface of the locking member to reduce the friction, althoughit is not particularly illustrated, the tapered surface of theinterposition member may be a concave curved surface, the inclinedsurface of the locking member may be a convex curved surface, or boththe tapered surface of the interposition member and the inclined surfaceof the locking member may be an uneven curved surface.

Furthermore, in the above-described embodiment 1, one auxiliary wedgeportion 18 provided in the locking member 15 is provided between thefront wedge portion 17 and the rear wedge portion 16, but as a modifiedexample of the locking member of the present invention, as illustratedin FIG. 8(a), a locking member 25 may be provided with two auxiliarywedge portions 18 and 18 between the front wedge portion 17 and the rearwedge portion 16 so as to be able to further regulate biting of thefront wedge portion 17 into the pipe spigot 2. Furthermore, theauxiliary wedge portion of a predetermined number of three or more maybe provided between the front wedge portion and the rear wedge portion.

Furthermore, in the above-described embodiment 1, one auxiliary wedgeportion 18 provided in the locking member 15 is provided between thefront wedge portion 17 and the rear wedge portion 16, but as anothermodified example of the locking member of the present invention, asillustrated in FIG. 8(b), a locking member 35 may be provided with theauxiliary wedge portion 18 on the front side in the pipe axis directionof the fluid pipe from the front wedge portion 17.

Furthermore, in the above-described embodiment 1, the locking member 15is pressed by the bolt 13 via the interposition member 14, but is notlimited thereto, the locking member 15 may be directly pressed by thebolt 13 instead of using the interposition member, and the lockingmember 15 may be pressed by the main body member 11.

Example 2

A separation preventing device according to the example 2 will bedescribed with reference to FIGS. 1 to 4 and 9 to 13. In addition, it isnot described about the constitution which is the same as the example 1mentioned above.

As illustrated in FIGS. 3(a) and 3(b), the locking member 15 has aconvex portion 15 b having an inclined surface 15 a formed on an outerperipheral portion of the center in circumferential direction, and theinclined surface 15 a increases in diameter and tilts so as to be awayfrom the outer peripheral surface 2 b of the pipe spigot 2 toward thefront side in the pipe axis direction of the pipe spigot 2. Further, theinclined surface 15 a is formed with convex portion end surface 15 fthat is substantially perpendicular to the pipe axis on the rear side inthe pipe axis direction, and the convex portion end surface 15 f isconnected to the peripheral side portion 15 k via the inclined surfaces15 h and 15 j. Furthermore, the convex portion end surface 15 f makes upa central portion 15 g of the present invention.

The peripheral side portion 15 k is formed in a substantially arcuateshape having a predetermined circumferential width on either side in thecircumferential direction from the central portion 15 g. As illustratedin FIG. 2(b), the front side wall 15 p of the locking member 15 facesthe front side wall 12 a of the recess portion 12, the peripheral sideportion inclined surface 15 m of the peripheral side portion 15 k of thelocking member faces the pressing wall 12 b of the recess portion 12,and as will be described below, the locking member is adapted to be ableto move and tilt between the front side wall 12 a and the pressing wall12 b of the recess portion 12.

Furthermore, as illustrated in FIG. 12(b), the peripheral side portioninclined surface 15 m of the locking member 15 tilts toward the frontside in the pipe axis direction of the pipe spigot 2 from the contactportion 15 n at a predetermined angle as it goes toward the inner sidein the radial direction (the inward radial direction) of the pipe spigot2.

Hereinafter, the behavior of the separation preventing device 10 whenforce is applied in the separation direction of the pipe axis of thepipe spigot 2 from the start of the initial clamping of the bolt 13screwed into the main body member 11 will be described.

As illustrated in FIGS. 9(a) and 9(b), the center of the bolt 13 screwedto the main body member 11 is set at a position shifted to the rear sideof the pipe axis from the central position of the length dimension inthe pipe axis direction of the interposition member 14, and at aposition shifted to the rear side of the pipe axis from the position ofthe rear wedge portion 16 of the locking member 15. Furthermore, betweenthe interposition member 14 and the bottom housing portion 12 e, andbetween the locking member 15 and the recess portion 12, gaps that allowthe movement and tilting of the interposition member and the lockingmember 15 are formed. For that reason, when initially slightly clampingthe bolt 13, the interposition member 14 moves to the rear side in thepipe axis direction of the pipe spigot 2 and is set in the state ofslightly coming into contact with the rear side wall 12 f of the bottomhousing unit 12 e, or the locking member 15 is set in the state ofslightly coming into contact with the front side wall 12 a of the recessportion 12 of the main body member 11 while tilting in acounterclockwise direction. Moreover, in the state in which the lockingmember 15 tilts in the counterclockwise direction, the rear wedgeportion 16 slightly comes into contact with the outer peripheral surface2 b of the pipe spigot 2, and the front wedge portion 17 and theauxiliary wedge portion 18 become the non-contact state from the outerperipheral surface 2 b of the pipe spigot 2 with clearances c1 and c2,respectively.

Next, as illustrated in FIGS. 10(a) and 10(b), when clamping the bolt 13by predetermined initial clamping torque, since the center of the bolt13 is set in the state of being shifted to the rear side of the pipeaxis from the position of the rear wedge portion 16 of the lockingmember 15, the interposition member 14 is strongly pressed against therear side wall 12 f of the bottom housing portion 12 e or the front sidewall 15 p of the locking member 15 is strongly pressed against the frontside wall 12 a of the recess portion 12, by the initial clamping forcedue to the bolt 13. At the same time, the initial clamping force due tothe bolt 13 is mainly concentrated on the rear wedge portion 16 of thelocking member 15, and the rear wedge portion 16 mainly bites into theouter peripheral surface 2 b of the pipe spigot 2. Furthermore, thefront wedge portion 17 becomes a state of non-contact with the pipespigot 2 or a state of slight-contact with the pipe spigot 2, and theauxiliary wedge portion 18 maintains the non-contact state with aclearance c3 from the outer peripheral surface 2 b of the pipe spigot 2.Furthermore, since the pressing surface 13 a of the bolt 13 is formed ina plane, the bolt 13 is able to press a pressing target surface 14 b ofthe interposition member 14 over a wide range, and thus, it is possibleto apply the pressing force substantially over the entire length of thecircumferential length of the wedge portions 16, 17 and 18.

Next, when the separating force is exerted in the pipe axis direction ofthe pipe spigot 2 from the initial clamping, as illustrated in FIGS.11(a) and 11(b), the point of the biting portion of the pipe spigot 2 ofthe rear wedge portion 16 of the locking member 15 moves to the rearside in the pipe axis direction together with the pipe spigot 2, and thelocking member 15 is pressed by the interposition member 14 by the wedgeeffect. Moreover, the locking member 15 tilts about the point of thebiting portion of the rear wedge portion 16 in the clockwise direction,the rear wedge portion 16 and the front wedge portion 17 bite into theouter peripheral surface 2 b of the pipe spigot 2, and the auxiliarywedge portion 18 does not come into contact with or slightly come intocontact with the outer peripheral surface 2 b of the pipe spigot 2.Furthermore, the separating force in the pipe axis direction of the pipespigot 2 in this state is held by the two wedge portions of the frontwedge portion 17 and the rear wedge portion 16 of the locking member 15.

When the pipe spigot 2 further moves to the separation side in the pipeaxis direction, as illustrated in FIG. 12(a), the portion of the bitingportion of the pipe spigot 2 of the rear wedge portion 16 of the lockingmember 15 further moves to the rear side in the pipe axis directiontogether with the pipe spigot 2, the locking member 15 is pressed by theinterposition member 14 by the wedge effect and tilts around the pointof the biting portion of the rear wedge portion 16 in the clockwisedirection, and the amount of biting of the rear wedge portion 16 and thefront wedge portion 17 into the outer peripheral surface 2 b of the pipespigot 2 further increases. Then, the auxiliary wedge portion 18 startsto bite into the pipe spigot 2. When the auxiliary wedge portion 18starts to bite into the pipe spigot 2, since the pressing force to thelocking member 15 from the interposition member 14 is also held by theauxiliary wedge portion 18, biting of the front wedge portion 17 intothe outer peripheral surface 2 b is regulated. Furthermore, in thisstate, the separating force in the pipe axis direction of the pipespigot 2 is held by the three wedge portions of the front wedge portion17, the rear wedge portion 16, and the auxiliary wedge portion 18.

At the same time, as illustrated in FIG. 12(b), when the pipe spigot 2moves to the rear side in the pipe axis direction, the vicinity of thecontact portion 15 n of the locking member 15 comes into contact withthe pressing wall 12 b of the recess portion 12, and the movement of thepipe spigot 2 almost stops. Furthermore, when the vicinity of thecontact portion 15 n of the peripheral side portion 15 k of the lockingmember 15 starts to come into contact with the pressing wall 12 b of therecess portion 12, a gap L2 which widens to the inner side in the radialdirection of the pipe spigot 2 is formed between the peripheral sideportion inclined surface 15 m of the locking member 15 and the pressingwall 12 b of the recess portion 12.

Moreover, as illustrated in FIGS. 13(a) and 13(b), finally, the lockingmember 15 tilts about the vicinity of the contact portion 15 n by thepressing force from the interposition member 14 due to the wedge effect,the peripheral side portion inclined surface 15 m comes into contactwith the pressing wall 12 b, the movement of the pipe spigot 2 stops,three wedges of the wedge portions 16, 17, and 18 bite into the pipespigot 2 by tilting around the vicinity of the contact portion 15 n, andthus, the locking member 15 is able to prevent the separation of thepipe spigot 2 in the pipe axis direction.

The separation preventing device of the present invention according tothe example 2 exhibits the following effects.

As illustrated in FIGS. 12(a) and 13(a), the convex portion end surface15 f of the central portion 15 g of the locking member 15 does not comeinto contact with the rear side wall 12 f of the recess portion 12,while the central portion 15 g of the locking member 15 allows themoderate movement and tilting, the wedge portions 16, 17 and 18 near thecentral portion 15 g of the locking member 15 press the pipe spigot 2.Accordingly, it is possible to prevent the excessive biting into thepipe spigot 2. That is, since the central portion 15 g of the lockingmember 15 is directly supported by the bolt 13 and the interpositionmember 14, the central portion 15 g of the locking member 15 is rarelydeformed, and so the wedge portion 16, 17 and 18 near the centralportion 15 g excessively bite into the pipe spigot 2. For this reason,in the state of separating the convex portion end surface 15 f of thecentral portion 15 g of the locking member 15 from the rear side wall 12f of the recess portion 12, by weakening the supporting rigidity of thecentral portion 15 g of the locking member 15 to allow the appropriatemovement and tilting, it is possible to prevent the excessive biting ofthe wedge portions 16, 17, and 18 near the central portion 15 g of thelocking member 15.

In addition, the central portion 15 g of the locking member 15 ispressed and supported right above by the bolt 13 and the interpositionmember 14, but the peripheral side portion 15 k of the locking member 15is not directly supported by the bolt 13 and the interposition member14. As a result, the peripheral side portion 15 k of the locking member15 becomes a state of a cantilever and is not sufficiently pressedagainst the pipe spigot 2, and the wedge portions 16, 17 and 18 of theperipheral side portion 15 k of the locking member 15 cannotsufficiently bite into the pipe spigot 2.

To solve the problem, as illustrated in FIG. 12(b), when the vicinity ofthe contact portion 15 n of the peripheral side portion 15 k of thelocking member 15 becomes a state of coming into contact with thepressing wall 12 b of the recess portion 12, the peripheral side portion15 k of the locking member 15 becomes a state of being supported by thepressing wall 12 b of the recess portion 12, thereby being able tosuppress the deformation of the peripheral side portion 15 k of thelocking member 15. Moreover, as illustrated in FIGS. 13(a), and 13(b),since the locking member 15 tilts about the vicinity of the contactportion 15 n in the state in which the deformation of the peripheralside portion 15 k of the locking member 15 is suppressed, the wedgeportions 16, 17, and 18 near the peripheral side portion 15 k of thelocking member 15 can reliably bite into the pipe spigot 2, and thus, itis possible to firmly prevent the separation of the pipe spigot 2 in thepipe axis direction.

As illustrated in FIG. 12(b), since the peripheral side portion 15 k ofthe locking member 15 is equipped with the peripheral side portioninclined surface 15 m that tilts toward the inner side in the radialdirection of the pipe spigot 2 and toward the front side in the pipeaxis direction from the contact portion 15 n, even after the peripheralside portion 15 k comes into contact with the recess portion 12, thelocking member 15 further tilts, and the wedge portions of theperipheral side portion 15 k of the locking member 15 can further biteinto the pipe spigot 2. Accordingly, it is possible to firmly preventthe separation of the pipe spigot 2 in the pipe axis direction.

As illustrated in FIG. 3, since the dimension in the pipe axis directionof the central portion 15 g of the locking member 15 is formed to begreater than the dimension in the pipe axis direction of the peripheralside portion 15 k of the locking member 15, it is possible to reliablyhold the bending moment applied to the peripheral side portion 15 k ofthe locking member 15.

Since the recess portion 12 is equipped with the pressing wall 12 bcoming into contact with the peripheral side portion 15 k of the lockingmember 15, and the rear side wall 12 f facing the central portion 15 gof the locking member 15, when the pipe spigot moves in the separationdirection, the peripheral side portion 15 k of the locking member 15 issupported while coming into contact with the pressing wall 12 b of therecess portion 12, and thus, it is possible to reduce the deformation ofthe peripheral side portion 15 k. Furthermore, since the central portion15 g of the locking member 15 faces the rear side wall 12 f of therecess portion 12, the wedge portions of the central portion 15 g pressthe pipe spigot 2, while being allowed the moderate movement andtilting. Accordingly, it is possible to prevent excessive biting intothe pipe spigot 2 and to prevent damage to the lining of the pipe spigot2.

Example 3

A separation preventing device according to the example 3 will bedescribed with reference to FIGS. 1 to 4 and 14 to 18. In addition, itis not described about the constitution which is the same as theexamples 1 and 2 mentioned above.

Hereinafter, the behavior of the pipe joint 1 when the external forcesuch as earthquake is repeatedly applied back and forth in the pipe axisdirection with respect to the pipe joint 1 equipped with a separationpreventing device 10 described above will be described.

As illustrated in FIG. 14(a), in an initial clamping state before theexternal force such as earthquake is applied, the pressing force due tothe clamped bolt 13 is transmitted to the locking member 15 via theinterposition member 14, and at least a rear wedge portion 16 of thelocking member 15 bites into the outer peripheral surface of the pipespigot 2. Furthermore, in the initial state, only the rear wedge portion16 may bite into the outer peripheral surface of the pipe spigot 2, or afront wedge portion 17 may bite in addition to the rear wedge portion16.

In this initial clamping state, since the pressing force of the pipespigot 2 in the radial direction due to the bolt 13 is transmitted bybeing branched in the pipe axis direction by the surface contact betweenthe tapered surface 14 a of the interposition member 14 and the inclinedsurface 15 a of the locking member 15, the interposition member 14 isdisposed at the rear in the recess portion 12, and the locking member 15is disposed at the front in the recess portion 12. That is, in thepresent embodiment, since the tapered surface 14 a of the interpositionmember 14 and the inclined surface 15 a of the locking member 15 areformed in a planar shape tilting substantially in parallel and facingeach other in the initial clamping state, the tapered surface 14 a andthe inclined surface 15 a come into surface-contact with each other.

At this time, in order from the rear side in the pipe axis direction,each of the members 13, 14, and 15 is disposed to be a position (P1) ofthe rear edge 13 b of the pressing surface 13 a of the bolt 13, aposition (P2) of the rear end surface 14 c of the interposition member14, and a position (P3) of the rear end surface 15 c of the lockingmember 15.

Furthermore, in the initial clamping state, a gap portion K whichpermits movement of the interposition member 14 in a predetermined widthin the pipe axis direction and tilting of the interposition member 14 ina predetermined angle is formed in front of the interposition member 14in the recess portion 12. That is, the interposition member 14 isdisposed in the recess portion 12 so as to be movable and tiltable inthe pipe axis direction.

Next, as illustrated in FIGS. 14(a) and 14(h), when the external forceacts on the rear side in the pipe axis direction with respect to thepipe spigot 2, that is, in a direction separated from the pipe socket 3,the locking member 15 biting into the outer peripheral surface of thepipe spigot 2 in the initial clamping state moves in the recess portion12 to the rear side in the pipe axis direction together with the pipespigot 2. As the inclined surface 15 a of the locking member 15 slidesalong the tapered surface 14 a of the interposition member 14 by theexternal force, a part of the external force in the pipe axis directionbecomes a component force (see FIG. 14(a)) in the directionperpendicular to the tapered surface 14 a, the locking member 15 ispressed in the inner radial direction of the pipe spigot 2, and the rearwedge portion 16 and the front wedge portion 17 of the locking member 15further bite into the outer peripheral surface 2 b of the pipe spigot 2.

Furthermore, as illustrated in FIG. 14(b), since the reaction forceagainst the biting of the rear wedge portion 16 and the front wedgeportion 17 acts, the interposition member 14 tilts in an illustratedclockwise direction around a part of the rear end side of the pressingtarget surface 14 b coming into surface-contact with a pressing surface13 a of the bolt 13 as a tilting center. At this time, as describedabove, since the position (P2) of the rear end surface 14 c of theinterposition member 14 is disposed in front in the pipe axis directionfrom the position (P1) of the rear edge 13 b of the pressing surface 13a of the bolt 13, the tilting center of the interposition member 14 doesnot slide-contact with the rear edge 13 b of the pressing surface 13 aof the bolt 13, and it is possible to avoid damage to the rear edge 13b.

Furthermore, since the pressing target surface 14 b of the interpositionmember 14 tilts with respect to the pressing surface 13 a of the bolt 13along with tilting of the interposition member 14, a shock-absorbing gapR1 described below is generated between the front side of the pressingtarget surface 14 b of the interposition member 14 and the pressingsurface 13 a of the bolt 13.

Next, as illustrated in FIG. 15(a), when the external force acts in thefront in the pipe axis direction with respect to the pipe spigot 2, thatis, in a direction inserted into the pipe socket 3, the locking member15 biting into the outer peripheral surface of the pipe spigot 2 movesforward in the pipe axis direction in the recess portion 12 togetherwith the pipe spigot 2. Moreover, a front end portion 2 c of the pipespigot 2 comes into contact with an inner end surface 3 c of the pipesocket 3, and thus, the movement of the pipe spigot 2 is regulated andcompleted. When the movement of the pipe spigot 2 is completed in thisway, since the gap between the front surface of the locking member 15and the front side wall 12 a of the recess portion 12 still remains, andthe locking member 15 does not collide with the recess portion 12, it ispossible to avoid the damage to the locking member 15. Furthermore, ashock-absorbing material for absorbing the shock due to the contact maybe provided between the front end portion 2 c of the pipe spigot 2 andthe inner end surface 3 c of the pipe socket 3.

Furthermore, as illustrated in FIG. 15(a), since the gap (R2) betweenthe pressing surface 13 a of the bolt 13 and the pressing target surface14 b of the interposition member 14 increases in accordance with themovement of the pipe spigot 2, the interposition member 14 appropriatelymoves within the recess portion 12 between the bolt 13 and the lockingmember 15 according to the gravity. For example, as illustrated in FIG.15(a), the pressing target surface 14 b of the interposition member 14is separated from the pressing surface 13 a of the bolt 13, the taperedsurface of the interposition member 14 and the inclined surface 15 a ofthe locking member 15 slide, and thus, the contact location betweenthese members 14 and 15 changes.

Next, as illustrated in FIG. 15(b), when the external force acts on thepipe spigot 2 in a direction of being separated from the pipe socket 3again, the locking member 15 biting into the outer peripheral surface ofthe pipe spigot 2 moves backward in the pipe axis direction in therecess portion 12 together with the pipe spigot 2. The inclined surfaces15 a of the locking member 15 slides along the tapered surface 14 a ofthe interposition member 14 by the external force, and a predeterminedlocation of the pressing target surface 14 b of the interposition member14 comes into contact with the pressing surface 13 a of the bolt 13.

Since the contact location of the pressing surface 13 a of the bolt 13coming into contact with the pressing target surface 14 b of theinterposition member 14 is a predetermined location on the front side inthe pipe axis direction from the position (P1) of the rear edge 13 b, itis possible to avoid damage to the rear edge 13 b. Furthermore, thecontact location between the pressing target surface 14 b of theinterposition member 14 and the pressing surface 13 a of the bolt 13 inFIG. 15(b) is a new location different from the above-described contactlocation in FIG. 14(a).

In addition, the pressing target surface 14 b of the interpositionmember 14 in FIG. 15(b) tilts with respect to the pressing surface 13 aof the bolt 13, and a shock-absorbing gap (R3) is formed between thefront of the pressing target surface 14 b of interposition member 14 andthe pressing surface 13 a of the bolt 13. Accordingly, since theinterposition member 14 coming into contact with the new locationtemporarily tilts based on the shock-absorbing gap (R3) as an acceptablevalue, the interposition member 14 and the bolt 13 do not stronglycollide with each other, and thus, it is possible to absorb the shock.

Hereinafter, similarly, when the external force such as earthquakerepeatedly acts on the pipe joint 1 back and forth in the pipe axisdirection, the interposition member 14 and the bolt 13 are not locallyconcentrated and come into contact with each other, and the contactlocation between the interposition member 14 and the bolt 13 isdispersed each time when the external force is repeated back and forthin the pipe axis direction. Accordingly, it is possible to avoid damagedue to the repeatedly concentrated shock between the members.

Next, modified examples of the interposition member of the presentinvention will be described. As illustrated in FIG. 16, in aninterposition member 24 as a first modified example of the presentinvention, a tapered surface 24 a is formed on a concave curved surface,in the initial state of the pipe joint described above, the taperedsurface 24 a partially comes into contact only with both front and rearend portions in the pipe axis direction of the inclined surface 15 a ofthe locking member 15, and is separated from an intermediate portion inthe pipe axis direction.

In this way, since the gap region between the tapered surface 24 a ofthe interposition member 24 and the inclined surface 15 a of the lockingmember 15 increases, it is possible to widen the shock-absorbing gapwhen the external force such as earthquake is repeatedly applied backand forth in the pipe axis direction.

Furthermore, as illustrated in FIG. 17, in an interposition member 34 asa second modified example of the present invention, a tapered surface 34a is formed on a convex curved surface, in the above-described initialstate of the pipe joint, the tapered surface 34 a partially comes intocontact only with the location except for the end portion in the pipeaxis direction of the inclined surface 15 a of the locking member 15,and is separated from both front and rear end portions in the pipe axisdirection.

In this way, since the gap region between the tapered surface 34 a ofthe interposition member 34 and the inclined surface 15 a of the lockingmember 15 increases, it is possible to widen the shock-absorbing gapwhen the external force such as earthquake is repeatedly applied backand forth in the pipe axis direction.

Furthermore, in place of the interposition members 24 and 34 of theabove-described first and second modified examples, or in addition tothe interposition members 24 and 34, the inclined surface of the lockingmember may be formed on a curved surface, and for example, the inclinedsurface of the locking member coming into contact with the taperedsurfaces 24 a and 34 a of the interposition members 24 and 34 may beformed on a convex curved surface or a concave curved surface configuredto complement the mutual surface shapes.

Furthermore, although it is not particularly illustrated, the pressingsurface of the bolt may be a convex curved surface or a concave curvedsurface, and in place of the pressing surface of the bolt, or inaddition to the pressing surface of the bolt, the pressing targetsurface of the interposition member may also be formed on the concavecurved surface or the convex curved surface. With such a configuration,it is also possible to secure the shock-absorbing gap when the externalforce such as earthquake is repeatedly applied back and forth in thepipe axis direction between the pressing surface of the bolt and thepressing target surface of the interposition member.

The separation preventing device of the present invention according tothe example 3 exhibits the following effects.

Even when the external force for separating or inserting the fluid pipeis applied to the fluid pipe in the pipe axis direction, as theinterposition member 14 between the locking member 15 and the bolt 13 asa pressing member moves in the recess portion 12 of the main body member11 in the pipe axial direction by an acceptable value of a predeterminedwidth, the tapered surface 14 a of the interposition member 14 changesthe contact portion with the outer surface of the locking member 15.Accordingly, even when the external force in the pipe axis direction forseparating and inserting the fluid pipe is repeated, since it ispossible to disperse the mutual contact locations so that the lockingmember 15, the bolt 13, and the interposition member 14 do not locallyconcentrate and collide with one another, it is possible to preventdamage to the members 13, 14, and 15 due to the repeated concentrationcollision, and thus, it is possible to firmly maintain the separationpreventing function of the fluid pipe, thereby being able tosatisfactorily hold the piping structure of the initial connection.

Furthermore, since the tapered surface 14 a of the interposition member14 and the inclined surface 15 a of the locking member 15 come intocontact with each other substantially in parallel in a tilting state, itis possible to ward off the external force by the sliding-contactbetween the parallel surfaces tilting with respect to the pipe axisdirection, without directly receiving the external force acting in thepipe axis direction.

Furthermore, as the interposition member 14 moves in the recess portion12 of the main body member 11 in the pipe axis direction by anacceptable value of a predetermined width, by allowing the interpositionmember 14 to tilt with respect to the bolt 13, it is possible to holdthe pressing force so that the bolt 13, the interposition member 14, andthe locking member 15 are not separated from one another even by themovement of the interposition member 14.

Furthermore, as illustrated in FIG. 18, since the bolt 13 is provided inthe main body member 11 so as to be movable back and forth in the radialdirection of the pipe spigot 2, during the operation of moving the bolt13 back and forth in the radial direction, an operating means such as atool T does not interfere with the outer surface of the pipe spigot 2.

Furthermore, since the interposition member 14 does not come intocontact with the rear edge 13 b of the pressing surface 13 a of the bolt13, it is possible to prevent damage to the rear edge 13 b, and it ispossible to vary the tilting center of the interposition member 14 andthe tilting center of the locking member 15 in the pipe axis direction.Accordingly, it is possible to increase the variation of the tiltingaspects of the interposition member 14 and the locking member 15,thereby always being able to press the locking member 15 in response tovarious directions and magnitudes of the external force.

Example 4

A separation preventing device according to the example will bedescribed with reference to FIGS. 1 to 4, 19 and 20. In addition, it isnot described about the constitution which is the same as the examples1-3 mentioned above.

As illustrated in FIG. 2(a), the peripheral side wall 12 d is providedwith a stepped portion with which an elastic body 19 to be describedlater is engaged. However, the stepped portion may not be provided.

Hereinafter, the aspect of fitting of the locking member forming theseparation preventing device of the present invention into the recessportion will be described.

As illustrated in FIGS. 3(a) and 3(b), the locking member 15 is formedin a substantially arcuate shape including arc-shaped wedge portions 16,17, and 18 along the outer peripheral surface of the pipe spigot 2, andis equipped with fitting grooves 15 d and 15 d at both end portions inthe circumferential direction of the locking member 15. As illustratedin FIGS. 2(a) and 2(b), the locking member 15 is housed in the recessportion 12 of the main body member 11, by fitting the elastic body 19having elasticity into the respective fitting grooves 15 d. Thus, thelocking member 15 is held within the recess portion 12 by the elasticrestoring force of the elastic body 19 that is elastically contracted bybeing compressed between the fitting groove 15 d and the peripheral sidewall 12 d of the recess portion 12, and thus falling out of the recessportion 12 is prevented.

As illustrated in FIG. 19, the elastic body 19 is made of, for example,elastic material, such as natural rubber of SBR, CR, and NBR or thelike, synthetic rubber, or resin, and in its natural state, the elasticbody 19 has a generally bullet shape in which a front end is ahemisphere surface and gradually increases in diameter toward a rearend, and is formed to be slightly greater than the inside of the fittinggroove 15 d.

The fitting groove 15 d is formed between the front wedge portion 17 andthe rear wedge portion 16, penetrates inward and outward in the radialdirection of the locking member 15, and groove wall portions 15 q and 15q constituting the fitting groove 15 d face each other so as to begradually narrowed in a tapered shape toward the outer radial directionat a predetermined tapered angle α.

Next, the fitting process of the elastic body 19 to the fitting groove15 d will be described. As illustrated in FIG. 19, the front end of theelastic body 19 is gradually inserted toward the outer radial side fromthe inner radial side of the fitting groove 15 d. Since the front endside of the elastic body 19 has a relatively small diameter and theinner diameter side of the fitting groove 15 d has a relatively largediameter, at the insertion intermediate stage of the elastic body 19,the outer surface of the elastic body 19 does not come intoslide-contact with the groove wall portions 15 q and 15 q of the fittinggroove 15 d, and thus, it is possible to avoid the distorted elasticdeformation of the elastic body 19.

The elastic body 19 fitted into the fitting grooves 15 d is pressuredbetween the facing groove wall portions 15 q and 15 q, the front endportion and the rear end portion of the elastic body 19 are slightlyelastically deformed and bulge, and as illustrated by a portionsurrounded by a dotted line of FIG. 19, the elastic restoring force D ofthe elastic body 19 acts in a direction perpendicular to the taperedsurface of each of the groove wall portions 15 q and 15 q.

More specifically the elastic restoring force D of the elastic body 19in the fitting groove 15 d is divided into a component force D1 facingthe outer radial side in a direction perpendicular to the pipe axis, anda component force in the pipe axis direction. By the component force D1in the direction perpendicular to the pipe axis, the locking member 15constituting the groove wall portions 15 q and 15 q is biased toward theouter diameter side in the direction perpendicular to the pipe axis, inother words, toward the inside of the recess portion 12.

Furthermore, as illustrated in FIGS. 19 and 20, the locking member 15 towhich the force component D1 is applied on the outer diameter side inthe direction perpendicular to the pipe axis presses the tapered surface14 a of the interposition member 14 that faces the inclined surface 15 aof the locking member 15 substantially in parallel. Therefore, asillustrated in FIG. 20, the component force D1 acting on the lockingmember 15 is further divided into a component force D2 facing the frontside in the pipe axis direction, and a component force in the directionperpendicular to the inclined surface 15 a. That is, the locking member15 is biased to the front side in the pipe axis direction within therecess portion 12 by the component force D2.

Meanwhile, as illustrated in FIG. 20, a reaction force D1′ of the samemagnitude acts on the interposition member 14 including the taperedsurface 14 a in the opposite direction of the component force D1. Thereaction force D1′ acting on the interposition member 14 is furtherdivided into a component force D2′ facing the rear side in the pipe axisdirection, and a component force in the direction perpendicular to thetapered surface 14 a. That is, the interposition member 14 is biased tothe rear side in the pipe axis direction within the recess portion 12 bythe component force D2′.

That is, according to the configuration of such fitting grooves 15 d, inthe locking member 15, by fitting the elastic body 19 into the fittinggrooves 15 d equipped with the groove wall portions 15 q and 15 q whichare gradually narrowed toward the outer radial direction, the elasticrestoring force gradually greatly acts toward the outer radialdirection, thereby pressing the groove wall portions 15 q and 15 qtoward the outer radial direction. As a result, the locking member 15 isbiased in the outer radial direction within the recess portion 12 by theelastic restoring force of the elastic body 19. As in the presentembodiment, in the structure of the separation prevention in which thebolt 13 provided in the main body member 11 is screwed to cause thelocking member 15 to bite into the outer peripheral surface 2 b of thepipe spigot 2 via the interposition member 14, where the locking member15 does not come into contact with the front side wall at the initialstate, a state in which the movement distance of the wedge action isreduced and the separation preventing force is reduced may occur, orwhere the interposition member 14 does not come into contact with therear side wall at the initial state, a state in which the interpositionmember 14 moves backward during wedging action of the locking member 15and the separation preventing force is reduced may occur. However, it ispossible to prevent these states by the elastic restoring force of theelastic body 19.

The separation preventing device of the present invention according tothe example 4 exhibits the following effects.

Since the elastic restoring force of the elastic body 19 fitted into thefitting grooves 15 d formed tapering toward the outer diameter directionof the pipe spigot 2 acts stronger as it goes toward the outer diameterside, the locking member 15 can be reliably housed without falling outof the interior of the recess portion 12, and when the locking member 15housed in the recess portion 12 moves or tilts, since the elastic body19 fitted into the fitting groove 15 d follows the movement of thelocking member 15, the elastic body 19 is not detached from the recessportion 12 and does not affect the movement and tilting of the lockingmember 15, and the locking member 15 can move or tilt as designed.

Furthermore, since the fitting grooves 15 d are formed between theplurality of wedge portions 16 and 17 provided on the locking member 15,it is possible to form the fitting grooves 15 d by effectively utilizingthe space between the wedge portions without dominating the regions ofthe plurality of wedge portions 16 and 17, the fitting grooves 15 d donot affect the locking capability of the locking member 15.

Furthermore, since the elastic body 19 elastically deformed in thepenetration direction of the fitting grooves 15 d comes into contactwith the inner wall of the recess portion 12 or the outer peripheralsurface 2 b of the pipe spigot 2, the elastic body 19 can be made tofunction as a cushioning material.

Furthermore, by the locking member 15 biased to the inside of the recessportion 12, it is possible to clamp the interposition member 14 betweenthe bolt 13 and the locking member 15, and by converting the elasticrestoring force acting in the outer radial direction into the pipe axisdirection using the tapered surface 14 a of the interposition member 14by the elastic body 19 fitted into the fitting grooves 15 d having thetapered width toward the outer radial direction, it is possible to biasthe interposition member 14 toward a predetermined position in the pipeaxis direction.

The embodiments 1-4 of the present invention have been described withreference to the drawings, but the specific configuration is not limitedto these embodiments, and modifications and additions within the scopethat does not depart from the scope of the present invention are alsoincluded in the present invention.

For example, in the above-described embodiments 1-4, the main bodymember 11 equipped with the recess portion 12 was described as being agland which is fixedly connected to the pipe socket 3 by the fasteningmember 4, but for example, the main body member may be a reinforcingbracket for increasing the holding ability of the pipe joint, or themain body member may be a pipe socket itself into which the pipe spigotas the fluid pipe is inserted, and a recess portion for housing thelocking member may be formed in the receiving unit of the pipe socket.

Furthermore, for example, in the above-described embodiments 1-4, therespective surfaces of the bolt 13, the interposition member 14, and thelocking member 15 directly abut against one another or come intoslide-contact with one another, but for example, all or part of thesurface of the interposition member may be coated with a rubber liningor the like, or a shock-absorbing material made of rubber, resin or thelike may be provided on the tapered surface of the interposition memberor the inclined surface of the locking member. According to such aconfiguration, when the external force such as the earthquake isrepeatedly applied back and forth in the pipe axis direction, it ispossible to absorb the shock that is loaded on each member within therecess portion.

REFERENCE NUMERALS

-   1 pipe joint-   2 pipe spigot (fluid pipe)-   2 b outer peripheral surface-   2 c front end portion-   3 pipe socket-   4 fastening member-   5 sealing member-   10 separation preventing device-   11 main body member-   12 recess portion-   12 a front side wall-   12 b pressing wall-   12 f rear side wall-   bolt (pressing member)-   13 a pressing surface-   13 b rear edge-   14 interposition member (pressing member)-   14 a tapered surface-   14 b pressing target surface-   14 c rear end surface-   15 locking member-   15 a inclined surface-   15 b convex portion-   15 c rear end surface-   15 d fitting groove-   15 e bottom-   15 f convex portion end surface-   15 g central portion-   15 k peripheral side portion-   15 m peripheral side portion inclined surface-   15 n contact portion-   15 q groove wall portion-   16 rear wedge portion-   17 front wedge portion-   18 auxiliary wedge portion (projection portion)-   19 elastic body-   24 interposition member-   24 a tapered surface-   34 interposition member-   34 a tapered surface

What is claimed is:
 1. A separation preventing device of a fluid pipethat prevents separation of the fluid pipe in a pipe axis direction, theseparation preventing device comprising: a main body member that isexternally fitted to an outer peripheral surface of the fluid pipe andhas a recess portion facing the outer peripheral surface; a lockingmember that is housed in the recess portion in a tiltable manner and isable to bite into the outer peripheral surface of the fluid pipe; and apressing unit that is provided in the main body member and presses thelocking member, the locking member has a plurality of wedge portions ina front-back direction of a pipe axis of the fluid pipe, and anauxiliary wedge projection portion that regulates biting of a frontwedge portion of the plurality of wedge portions into the fluid pipe,when the fluid pipe moves to a separation side in the pipe axisdirection, wherein the projection portion is provided between a frontwedge portion and a rear wedge portion of the plurality of wedgeportions.
 2. The separation preventing device of a fluid pipe accordingto claim 1, wherein the projection portion is a wedge portion that bitesinto the fluid pipe at least by tilting.
 3. The separation preventingdevice of a fluid pipe according to claim 1, wherein a leading end ofthe projection portion does not project from a line that connects aleading end of the front wedge portion and a leading end of the rearwedge portion.
 4. The separation preventing device of a fluid pipeaccording to claim 1, wherein the wedge portions tilt to a front side inthe pipe axis direction of the fluid pipe.
 5. A pipe joint comprising:the fluid pipe; a pipe socket into which a front end portion of thefluid pipe is inserted; and the separation preventing device of thefluid pipe that prevents separation of the fluid pipe from the pipesocket according to claim 1.